Down Syndrome Eunji Yang & Rosemary Kim & Alice Gavarrete Biology Honors 24 February 2011
What is Down Syndrome • Down syndrome is a condition in which extra genetic material causes delays in the way a child develops, both mentally and physically.
Disorder Specialist • It is a chromosomal type of disorder. • It is also called Trisomy 21 or DS. • It affects chromosome number 21. • The karyotype of a person with DS has an extra copy of the 21st chromosome.
Down syndrome symptoms vary from person to person and can range from mild to severe. However, children with Down syndrome have a widely recognized appearance. Common physical signs include: • Decreased muscle tone at birth • Excess skin at the nape of the neck • Flattened nose • Separated joints between the bones of the skull (sutures) • Single crease in the palm of the hand • Small ears • Small mouth • Upward slanting eyes • Wide, short hands with short fingers • White spots on the colored part of the eye (Brushfield spots)
Testing Before Birth: 1.) Screen tests: estimate the risk that a fetus has DS • Nuchal translucency testing • Triple screen or quadruple screen • Integrated screen • Genetic ultrasound 2.) Diagnostic tests: can tell whether the fetus actually has the condition. • Chorionic villus sampling (CVS). • Amniocentesis. • Percutaneous umbilical blood sampling (PUBS).
Genetic Counselor • The child got the disorder by nondisjunction, when a pair of number 21 chromosomes fail to separate during the formation of an egg(or sperm). When the egg joins with a normal sperm to form an embryo , it ends up with three copies instead of the normal two. • In rare cases, Down syndrome is caused by a Robertsonian translocation, which occurs when the long arm of chromosome 21 breaks off and attaches to another chromosome at the centromere. The carrier of this won’t have DS, but can have children with the disorder.
The survival rate for children with DS is 88% alive at 1 year and 82% alive at 10 years. • The major cause of death in the first few years are caused by heart defects and/or heart failures. • Although, Down syndrome is not treatable, physical therapy and speech therapy can help people with the disorder to develop more normally. • Corrective surgery and screen tests for other medical problems can improve the life of people with DS. • Also, enriched environments increase the capacity to learn and to carry out a productive life style.
Besides the symptoms, there are other types of test to check for Down Syndrome. • A blood test to check for the extra chromosome • Echocardiograma (a test that uses sound waves to create a moving picture of the heart) to check for heart defects (usually done soon after birth) • Electrocardiogram (ECG)-a test that records the electrical activity of the heart. • X-rays of the chest and gastrointestinal tract
Parent of Down Syndrome • Children with Down syndrome are usually of average size, but they tend to grow at a slower and remain smaller than other peers. Kids with Down syndrome can and do learn, and are capable of developing skills throughout their lives. However, they reach goals at a different pace; usually delays in speech and self-care skills like feeding, dressing, and using toilet. • A child with Down syndrome can live to age fifty and beyond. However, because they consume lower amounts of calories but are more likely to be obese, enough physical activities is needed.
With rare exceptions, men with Down syndrome cannot father a child, whereas a woman with Down syndrome has a 50-50 chance of conceiving a child with Down syndrome, but many affected fetuses are miscarried. • The risk of giving a birth to a baby affected by Down syndrome increases along with the mother’s age. *At age 25, the risk of having a baby with Down syndrome is 1 in 1,250. *At age 30, the risk is 1 in 1,000. *At age 35, the risk is 1 in 400. *At age 40, the risk is 1 in 100. *At age 45, the risk is 1 in 30.
Against screening test and diagnostic test • We are against screening test and diagnostic test because… *Although the screening is not always accurate, if the parent of the child with DS finds out that their child has the disorder, there would be a higher chance for them to abort the child. *In diagnostic tests, the test is 99% accurate in detecting the disorder, and because the test is done in the mother’s uterus, the child can be miscarried. *We strongly believe that no child should have their right to life taken away.
* “Is prenatal diagnosis morally licit? If prenatal diagnosis respects the life and integrity of the embryo and the human fetus and is directed toward its safeguarding or healing as an individual, then the answer is affirmative” (sec. I, no. 2). from the Vatican Congregation for the Doctrine of the Faith called The Gift of Life (Donum Vitae). *As catholic students we believe what the church is teaching. *There are not many differences between people with DS and people without. Although their learning pace is slower than normal people, they can fully develop their learning skills
sOURCES • http://kidshealth.org/parent/medical/genetic/down_syndrome.html • http://www.nichd.nih.gov/publications/pubs/downsyndrome.cfm • http://www.nlm.nih.gov/medlineplus/ency/article/000997.htm • http://www.usccb.org/shv/testing.shtml